Damper control



. Jufi 4 1939. I 'A, D, COLE 2,164,607-

DAMPER CONTROL Filed Aug". 26, 1955 2 Sheets-Sheet 1 awe/44100 Ar H1111 D. C ole 19390 A. m. COLE ZZQEGLGQ? DAMPER common 7 Filed Aug. 26, 1955 2 Sheets-Sheet 2 swam kw Arthur D. Cole Patented July 4, 1939 UNITED STATES 7 DAMPER CONTROL Arthur D. Cole, Minneapolis, Minn.

Application August 26, 1935, Serial No. 37,842

16 Claims. (01. 236-45) My invention relates to dampers and damper controls and more specifically to draft regulators. An object of the invention resides in providing a draft regulator, particularly adapted to be installed in existing smoke pipes without removal or dismantling of the stove pipe or replacement of any of the sections thereof.

A still further object of the invention resides in providing a draft regulator which may be installed in a vertical horizontal or inclined stove pipe without reconstruction or rearrangement of the parts of the regulator.

Another object of the invention resides in providing a draft regulator which cannot be improperly installed.

An object of the invention resides in providing a draft regulator having a damper adapted to be inserted into the pipe through a relatively narrow circumferential opening in the pipe.

A feature of the invention resides in providing a draft regulator havinga case, a damper and a vane for operating the damper both disposed within the case, said damper being pivoted at both ends to the case and being adapted to be inserted into the pipe in which the device is to be installed.

Another object of the invention resides in providing a linkage, connected to the vane and damper for opwating the damper, saildilinkage being disposed exteriorly of the case.

An object of the invention resides in providing a damping device for preventing hunting or wagging of the control vane when changes in draft occur.

A still further object of the invention resides in providing a construction bymeans of which adjustment of the damping device may be procured.

Another object of the invention resides in constructing the damping device in the form of a shield adapted to cover the opening between the case and the exterior, whereby the flow of air into or out of the device through said opening may be controlled.

A feature of the invention resides in-providing .an angular space or corner between the pipe and the case lnwhich the said shield is disposed.

An object of the invention resides in constructing the case with a neck having parallel side walls spaced apart substantially the diameter of the pipe and adapted to be tangent to the pipe when the device is installed, said neck also having top and bottom walls constructed with arcuate edges adapted to fit against the pipe upon the exterior thereof.

Another object of the invention resides in providing extensions on the side walls of the neck adapted to be bent about the pipe and in further providing clamping means at the ends of the extensions for drawing the same together for the PATENT OFFICE purpose of causing the case to fit upon the pipe and for holding the case attached to the pipe.

An object of the invention resides in arranging the opening in the pipe through which the damper is inserted in a manner such that the damper never passes the edges of the opening when the damper is swung about its axis, thereby preventing catching of the damper on the edges of the pipe adjacent the opening therein and maintaining the damper throughout its movement within the confines of the pipe.

Another object of the invention resides in providing a strut between the walls of the neck having the arcuate slots for stiffening the same, said strut having shoulders thereon for engagement with the edges of the pipe at the opening therein, said shoulders serving to locate the device relative to the opening and to reinforce the pipe.

A still further object of the invention resides in constructing the movable parts of the invcntion so that the same are atall times balanced, whereby inaccuracies in the operation of the device are entirely eliminated.

A feature of the invention resides in utilizing with the invention a drum semi-circular in form to which a weighted flexible member is attached.

An object of the invention resides in the specific construction .of said drum.

An object of the invention resides in providing a device which will not be aifected by the accumulation of soot and scale within the pipe.

Other objects of the invention reside in the novel combination and arrangement of parts and in the details of construction hereinafter illustrated and/or described. 6

In the drawings:

Fig. 1 is a perspective view of a draft regulator iliustrating an embodiment of my invention and applied to a horizontally extending pipe.

Fig. 2 is a longitudinal sectional view taken on line 2-2 of Fig. i.

Fig, 3 is a view similar to Fig. 1 showing the draft regulator applied to a vertically extending pipe and viewed from the opposite side. of the regulator.

Fig. 4 is an elevational view of the regulator, showing the regulator mounted on an inclined pipe.

My invention may be used in conjunction with any device or apparatus through which the flow of a gas, occurs and in which theregulation of flow of such gas is desired. A common use of the invention is in conjunction with smoke pipes of heating plants and for the purpose of simplification, the following description of the invention will be confined to draft regulators to be used in conjunction with heating plants, though it can readily be comprehended that other applications of the invention are contemplated.

For the purpose of illustrating the application of my invention, I have shown a section of pipe which is indicated in Figs. 1 and 3 of the drawings in dotted lines and designated by the reference numeral I. This section of pipe forms a part of the smoke pipe of a heating plant with which the invention is to be used. The wall of the smoke pipe is indicated by the reference numeral l I and the passageway therethrough by the numeral l2. The flue gas flows through the passageway !2 from left to right as viewed in Fig. 1.

The draft regulator proper comprises a case N which supports all of the operating parts of the regulator and which is bodily applicable to the smoke pipe I and which may be attached thereto in an extremely simple and expedient manner. The case i3 is formed with a body portion l4 and a neck l5 issuing outwardly therefrom. The neck extends up to and is attached to the smoke pipe in while the body portion I4 projects outwardly from the smoke pipe and is spaced with respect thereto to provide a corner or angle therebetween. Pivoted to the wall structure of the neck 55 is a damper 56 which is disposed within the passageway l2 of smoke pipe l0 and which is adapted to control the flow of gas through said passageway. Within the body portion [4 of case i3 is disposed a vane i! which is subject to the pressure within the. passageway I2 and which functions to operate the damper IS. These various parts will now be described in detail.

The body portion of case l3 comprises two spaced side walls 18 and I9 which are of the shape of a segment of a circle. These two walls are parallel to one another and are attached to a radial wall 2| which extends completely across the case. The walls l8 and H! are provided at the arcuate edges thereof with inwardly turned arcuate flanges 22 and 23. A curved or arcuate wall 24 is secured to the flanges 22 and 23 and is integral with the wall 2i. The case I3 is open at the portion thereof opposite the radial wall It, the opening through said case being designated by the reference numeral 25. At the marginal edges of this opening are provided flanges 28 and 21 which are turned inwardly from the walls l8 and I9 and the wall 24.

The neck l5 comprises spaced side walls 52? and 28 which lie in continuation of the walls iii and E3 of the body portion i i and which are preferably constructed of the same sheets of material from which the said walls i8 and 39 are constructed. These walls have inwardly turned flanges 29 and 35 at the top and bottom thereof, the flanges 3i extending along walls l8 and i9 and being integral therewith. .ittached to these walls are parallel radial walls 32 and 33. The wall 32 forms a continuation of the wall of the body portion is of the case and is preferably constructed of the same sheet of material as said wall. The wall 33 is constructed of a separate sheet and is provided with an inwardly turned flange 3d, the purpose oi which will be subsequently more fully explained. This flange lies in the plane of the flanges 26 and 21 of the arcuate and side walls of the body portion is of the case l3.

The two walls 32 and 33 are constructed with arcuate edges 36 which are of the same curvature as the pipe l0 and are adapted to fit or seat against the wall H of said pipe. The width of the walls 32 and 33 and the arcuate wall 24 of the body portion H of the case is exactly equal to the external diameter of the pipe so that when the case is applied to the pipe, as shown in the drawings, the two side walls l2! and 22 he tangent to the pipe. On the two side walls iii and 28 are formed two extensions 3? and 38 which are adapted to be bent about the pipe when the same is applied thereto. These extensions have bent outwardly therefrom flanges M and 42 which are spaced from one another. A bolt H3 passes through these flanges and serves to draw the flanges together to tension the said extensions for the purpose of causing the case to fit the pipe and to Securely hold the regulator attached to the pipe.

For the purpose of reinforcing the neck $5 of the case 83, I utilize one or more struts 95 which extend between the walls 32 and 33 of said neck and which are welded or otherwise secured thereto. These struts are disposed at the periphery of the arcuate edge 36. On the struts 95 are formed shoulders 96 and 91 which extend inwardly into the pipe proper. These shoulders serve a purpose to be subsequently referred to.

Within the neck l5 and within the pipe i2 is mounted the damper I6. This damper consists of a disk constructed of sheet metal and of a diameter slightly less than the internal diameter of the pipe. This disk is formed at its center with a diametrally extending groove 43. A shaft I 44 is disposed within said groove and the said damper is welded to the shaft at suitable intervals along said shaft. Shaft 44 is journaled in the two side walls I21 and 28 of neck l5 and extends outwardly beyond the same. By means of this construction the damper may swing from the position shown in Fig. 1 to that shown in Fi 3.

Within the body portion i l of the case i3 is mounted the vane I1. This vane consists of a rectangular sheet of metal provided at one end with a beaded portion 45. A shaft 46 is disposed within said beaded portion and is welded thereto the same as the shaft 44 is secured to damper i6. Shaft 46 extends through the side walls 88 and IQ of the body portion 14 of case 93 and is journaled therein. The arcuate wall 24 of the case i3 is concentric with the axis of the shaft =36 and the two walls It! and i 9 are at right angles to said shaft so that the vane l 7 may swing from the full line position shown in Fig. 2 to the dotted line position and during such movement is in close proximity to the edges of the case so as to prevent appreciable leakage of air past the vane. The flange 35 on the radial wall of neck it and the flanges 38 and ill on the walls is 22s of the body portion it of the case serve as stops for limiting the movement the vane outwardly. Movement of the vane in the opposite direction is limited by the radial wall 26 .which the vane engages as shown in dotted lines in Fig. 2.

By means of the particular construction of case 63 a compartment 47 is formed within interior of the body portion 54 and in which the vane ll is movable. This compartment communicates through a passageway as in neck with the passageway 52 of the smoke pipe In operation the surface of the vane facing the interior of the case is subject to the pressure within the pipe 10 and serves to control the operation of the regulating device.

For operating the damper IS a linkage is used which is indicated in its entirety by the reference numeral 5|. This linkage comprises two cranks 52 and 53 which are attached to the shafts 44 and 46. Both cranks 52 and 53 are constructed th tn DCD (D in the same manner and only the construction of crank 52 will be described in detail. This crank is constructed from sheet metal and is formed with an elongated body portion from which issue two wings 55. The shaft id extends through the body portion 55 and the wings 55 are welded to the said shaft. Cranks 52 and 53 are connected together by means of a U-shaped link 56 which is pivoted to the said cranks through rivets 5? and 58 passing jointly through the link 56 and the corresponding crank. The two cranks 52 and 53 are exactly the same length and the distance between rivets 5i and 58 of link 55 is equal to the distance between the shafts tie and so so that the linkage 55 is always balanced and the damper and vane will never be thrown out of balance regardless of the position of said linkage.

Inasmuch as the damper i6 is attached medialiv to the shaft 44 the same is at all times balanced. The vane i'l being attached along an edge to the shaft 56, a counterweight 59 is utilized for counterhalanclng said vane.- Shaft 48 is provided at its end with an arm Bl which is bent outwardly therefrom and to which the said counterweight is attached. The counterweight is formed with a bore $2 for the reception of said arm and may be slid longitudinally along said arm to vary its distance from the center of the shaft 46. A set screw 63 threaded into the counterweight holds the same in adjusted position upon the arm' 6|. Arm El lies in the plane of the vane i1 so that said vane is perfectly balanced.

For the purpose of providing suitable resisting iorce to counteract the pressure of the hue gas against the vane ll, whereby regulation of the drait is procured, a construction is employed which is best shown in Fig. 1. Attached to the end or the shaft 68 protruding through the wall it or" case it? is a drum 64. This drum is constructed in the form of a semi-circular sheave. Drum 6 3 is constructed in two halves 55 and 68 formed of sheet metal pressed in the desired shape. These halves are provided with planiform semi-circular portions 6?- and outwardly flaring annular portions to. When the two halves are placed together with the semi-circuar por tions El in contact, the flared portions'til form a groove 8t therecetween. The said halves are '"urther constructed outwardly turned ii rages lli which lie in the common plane and in a plane parallel with the axis of the drum. Shaft .velded to ages (ill. drum S t attached to it at one end of the groove 59 a) a n l l, which chain has secured to the other end thereof a split cotter pin i2. A number or washers 83 mounted on this cotter pin form a weight it which provides the resisting force.

For the purpose of damping the action of the vane ll and to prevent hunting or wagging of said vane when the pressure with the smoke pipe varies, a shield "it is employed. This shield consists of a sheet of metal which is constructed with a body portion 8%. adapted to overlie the opening 2% in the case is. Said shield is further constructed with wings 1'5 and it which extend outwardly therefrom and embrace the two side walls l3 and is of the body portion M of the case. At the inner end of the body portion or shield i4 is a flange H which is secured to the radial wall 33 of neck l5 of the case through a sheet metal screw 78." The outer edge 19 of the shield i is free and is spaced from the flange 2'2 to provide an opening or outlet 85 which in lt extends th o gh the portions and occurs, shaft 44 is disposed in notches 9|.

communication with the portion oi the sham her at on the exterior oi the vane it through the opening 25. By moving the shield it toward and from the case t3, the dimensions or" the outlet 8i can be varied and the resistance to the flow of air into the compartment t! through the opening can be adjusted. The shield I4 is held in adjusted position by means of a bolt 82 which extends thrcugh said shield. 'Two nuts 83 and 84 on said bolt hold the shield in proper position. Bolt 82 is attached to a clip 85 which is welded to the wall 24 of the case.

The manner of installing my invention is as follows: For the purpose of explanation, it is assumed that the pipe i0 is so arranged that the chimney is connected to the left as viewed in Fig. 2 and the heating plant to the right. At the desired locality in the pipe where the regulator is to be installed, a circumferentially extending slot 86 is cut. This slot is relatively narrow, being bounded by two circumferentially extending edges 81 and 88 and two edges 89 extending along elements of the pipe and situated substantially diametrally opposite one another though slightly toward one side ofthe diametral plane. At the corners'formed by the edges 81 and. 89 are cut notches 9i. After the pipe has been so cut and the slot-86 and notches 9| formed, the draft regulator is arranged with the damper l6 disposed as shown in Fig. 3 and with the extensions 31 and 38 lying in the planes of the walls 52'! and 28 of'fhe case. The device is then slid into place with the two extensions 31 and 38 straddling the pipe. As the device is applied the struts 95 are inserted into the slot 86 of the pipe and the shoulders 98 and 9'! brought into engagement with the edges 81 and 88 thereof. The device is finally broughttoward the pipe until the arcuate edges 38 of the radial walls 32 and 38 seal; against the wall ll of the pipe. When this The two extensions 31 and 38 are then bent about the pipe and the bolt i 38 inserted through the flanges ii and zand said bolt tightened up. This attaches the regulator to the pipe and holds the same securely applied thereto. The regulator is now ready ior use.

In the use of the regulator it is merely necessary to adjust the weight iii applied to the drum to by changing the number of washers l3 mounted on cotter pin it. normal position when the draft is a minimum, the and vane oc= cupy the position shown in lines in 2. As draft increases suction in the pipe increases and exerts a pull upon the vane it, which swings the vane to the right. Such action is in opposition to the force produced by the weight ll). The swinging of the vane ll causes swinging of the damper 56 toward the position shown in dotted lines in Fig. 2, which tends tor cut off the flow of flue gas through the pipe and to reduce the draft. Vane ll stops at an intermediate position when a balance has been procured. The shield it is adjusted so that the outlet 8! is a maximum with no hunting or wagging of the vane it. Should such hunting commence the shield M is moved closer to the case and the area of the outlet 8! reduced. If the draft in the smoke pipe decreases the force is reduced and the weight l8 tends to swing the vane ll toward its full line position. This opens the damper and allows more flue gas to flow through the tube so that the draft through the smoke pipe remains the same. When the damper reaches its dotted line position, the same engages shoulder not collect soot and scale.

96 of strut which serves as a stop for limiting the movement thereof.

By arranging the shaft 46 in close proximity to the inlet l5 and the arcuate wall 24 remote from said inlet, a construction is provided which will not be affected by the accumulation of soot and scale within the pipe. When the device is on a horizontal 'pipe as shown in Fig. 2, the vane l1 throws the soot and scale back into the pipe every time the vane reaches the dotted line position. Changes in the weight of the vane through accumulationof soot and scale hence cannot occur when the device is thus installed. When the device is installed on a vertical or inclined pipe, as shown in Figs. 3 and 4, the vane is subjected on its under side to the flue gases and hence can- In neither installation is the curved wall 23 so disposed as to permit of accumulation of soot thereon. None of the walls along which the vane travels can hence collect soot or scale to obstruct movement of the vane and the device will hence function indefinitely without attention.

My invention is highly advantageous in that a simple and practical construction is provided which may be readily and quickly attached to an existing smoke pipe without dismantling or replacing any of the sections thereof. The device requires an extremely small amount of space longitudinally along the pipe and can hence be installed in crowded quarters as, for example, on a section of an elbow or in very short length of pipe. The slot in which the damper is posi-= tioned is extremely narrow and does not greatly weaken the pipe. By means of the struts em ployed, both the pipe and the case are reinforced. The shoulders and struts used with my invention serve to locate the case with respect to the pipe so that the device cannot be incorrectly applied. The shaft carrying the damper is supported at both ends so that an ex tremely sturdy construction is provided. All oi the linkage for the invention is disposed upon the exterior of the case, thereby preventing accumula tion of soot or scale upon the same and changing the operation of the regulator. By means of the semi-circular drum employed it becomes impossl ble to install the device incorrectly. if the chain can be made to ride wi in the groove of the drum the device will function.

Changes in the specific form of my invention,

the

thin a semi g therein and formed with parallel clzccuinie ntial edges bounding said a draft regulator including a case adapted to about the pipe and covering said opening, said case including spaced transverse walls, said walls being formed with arcuate edges adapted to fit against the pipe, a strut between said walls and disposed in proximity to said arcuate edges, and shoulders formed on said strut for engagement with the circumferential edges'of the pipe, said shoulders restraining longitudinal. movement of the case with respect to the pipe, and means for holding the case attached to the pipe.

2. In combination with a cylindrical pipe having a semi-circular opening therein and formed with parallel circumferential edges bounding said opening, a draft regulator including a case adapted to fit about the pipe and covering said opening, said case having transverse walls constructed with -arcuate edges adapted to fit against the pipe and being further constructed with side walls connected to said transverse walls and tangent to the pipe, a shaft journaled at its ends in said side walls and extending across the pipe, a strut between said transverse walls and positioned in proximity to said arcuate edges, said strut having a portion extending into'the pipe and a damper carried by said shaft, said portion of the strut forming a stop for limiting the movement of said damper.

3. A draft regulator comprising a case, two shafts arranged in parallel relation and pivoted to said case, a damper attached at its center to one of said shafts, a'regulating vane carried by one of said shafts, means for counterbalancing said regulating vane, cranks connected to said shafts and extending outwardly therefrom in parallel relation, said cranks being of the same length, and a link pivoted to said cranks, said link being of the same length as the distance between said shafts.

4. In combination with a cylindrical pipe having a semi-circular opening therein and formed with parallel circumferential edges partially bounding said opening and being formed with edges disposed substantially at diametrally cpposite lines extending along elements of the pipe and further bounding said opening and being further formed with notches at opposite corners of said opening, a case adapted to fit about the pipe and covering the opening, a shaft extending acrosssaid case and disposed within said notches,

and a'damper mounted on said shaft and adapted to swing in one position parallel to two of the circumferential edges and in another position at right angles thereto and parallel to the second named edges, said damper in both extreme positions being within the confines of the pipe and being free from said opening.

5. In combination with a pipe, a draft regulator including a case having a chamber there in, a damper within the pipe, a vane Within said chamber means actuated by said vane for oper ating said damper, said vane on one side thereof being subject to the pressure within the pipe and on the otherside thereof subject to atmospheric pressure, and a movable member connected to said case and forming in conjunction therewith a variable opening for damping the movement of said vane.

6. ."In combination with a pipe, 2. draft regulator including a case having a chamber therein, a damper the pipe, vane within chamber m ans actuated by said vane for operating said damper, said vane on one side thereof heing subject to the pressure within the pipe, said case having an cpening on the opposite side of said vane and said vane on such side being subject to atmospheric pressure, a shield guarding said opening, said shield being pivoted to said case along an edge of said opening and having wings thereon fitting against the sides of the case, said shield being spaced from the case at the edge thereof opposite said pivoted edge to form an outlet communicating with the chamber within said case upon the atmospheric side of the vane, and means for holding said shield in adjusted position with respect to the case.

7. In combination, a pipe, a case applied to said pipe and having a segmental shaped portion extending outwardly from the pipe and spaced therefrom to form a corner therebetween, a vane within the segmental shaped portion of said case,

said case being open on the side thereof facing said pipe, and a shield applied to such portion of the case and disposed within said corner, means for guiding said shield for movement toward and from the case, and means for holding the shield in adjusted position with respect to the case.

8. A draft regulator comprising a case, two shafts arranged in parallel relation and pivoted to said case, a damper attached to one of said shafts, a vane attached to the other of said shafts, linkage between said shaft and vane, a semicircular drum secuscd to one of said shafts with the diametral portion thereof substantially parallel with said damper, an elongated flexible member wrapped about said drum and a weight secured to the end of said member.

9. A draft regulator comprising a case, two shafts arranged in parallel relation and pivoted t said case, a damper attached to one of said shafts, a vane attached to the other of said shafts, linkage between said shaft and vane, a semi-circular drum secured to one of said shafts, said drum being constructed from two sheets of metal having outwardly flaring circular portions forming in conjunction a V-shaped groove and having flanges at the diametral portions thereof extending outwardly in opposite directions, said shaft extending through said drum in proximity to said flanges and being welded to said flanges, a flexible member secured to said drum and adapted to be wrapped about said groove and a weight attached to the end of said flexible member.

10. In combination with a cylindrical pipe having an opening therein, a draft regulator including a case adapted to fit about the pipe and covering said opening, said case including spaced transverse walls, said walls being formed with arcuate edges adapted to fit against the pipe and a strut extending between said walls and disposed in proximity to said pipe with an edge of said strut substantially at the arcuate edges of said transverse walls.

11. In combination with a pipe, a draft regulator including a case having a chamber therein, a damper within the pipe, a vane within said chamber, means actuated by said vane for, operat ng said damper, said vane on one side thereof being subject to the pressure within the pipe, said case having an opening subjecting the other side of the case to atmospheric pressure, a valve member movable relative to said opening for controlling the movement of air by said vane through said opening, and means for holding said valve member in adjusted position with respect to said case.

12. A draft regulator for application to a pipe, said regulator comprising a case having two substantially radial walls, a curved wall connecting said radial walls and parallel walls connected therewith, a vane, pivot means for said vane pivoted to said parallel walls'in' proximity to one of said radial walls and in spaced relation with the neck issuing outwardly from said case and in communication therewith, said neck having transverse walls of a width substantially equal to the diameter of the pipe and side walls connec ed thereto, said transverse walls being constructed with arcuategedges adapted to fit against the pipe, extensions on said side walls adapted to be bent about the pipe, means for drawing said extensions together to holdithe regulator attached to the pipe, a damper pivoted to the side walls of said neck and adapt :d to extend into the pipe when the regulator is applied thereto, a Vane pivoted within said case and subject through said neck to the pressure Within the pipe, and motion transmitting means connected to said damper and vane and moving said damper upo'n variation in pressure within the pipe.

14. A draft regulator for application to a pipe, said regulator comprising a case, a rectangular neck issuing outwardly from said case and in communication therewith, said neck having transverse walls of a Width substantially equal to the diameter of the pipe and side walls connected thereto, said transverse walls being constructed with arcuate edges adapted to fit against the pipe, means connected to said side walls for attaching the regulator to the pipe, said side walls having aligning bearings therein positioned in proximity to one of said other walls, a damper having a shaft journalled in said bearings, a vane pivoted within said case, and subjected to the pressure within the pipe, and motion transmitting means connected to said damper and vane and moving said damper upon variations of pressure in the pipe.

15. In combination with a cylindrical pipe having a passageway therethrough, a ,case on said pipe having a chamber comn unicating with said passageway, said case being constructed with two parallel walls spaced apart a distance equal to the diameter of the pipe, said walls being tangent to said pipe, a pivoted damper disposed between said walls and having its axis disposed transversely of said walls and substantially diametrally of said pipe, said damper being supported by said walls, a pivoted vane disposed within said case and having its axis disposed transversely of said walls, and in spaced substantially parallel relation with respect to the axis of said damper, said vane being supported by the same walls of said case and means for connecting said vane to said damper so that said damper is operated by said vane.

16. In combination with a cylindrical pipe having a passageway therethrough, a case on said pipe having a chamber communicating with said passageway, said case being constructed with two spaced walls parallel to the axes of the pipe/and issuing from the pipe along elements thereof, a pivoted damper disposed between said walls and having its axis disposed transversely of said walls and substantially diametrally of said pipe, said damper being supported by said walls, a pivoted vane disposed within said case and having its axis disposed transversely of said walls, and in spaced substantially parallel relation with respect to the axis of said damper, said vane being supported by the same walls of said case and means for connecting said vane to said damper so that said damper is operated by said vane.

ARTHUR D. COLE. 

